21,616 research outputs found

    Prediction of Drilled Shafts Axial Capacities Using CPT Results

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    Results from nineteen full-scale axial load tests are reviewed to compare methods for predicting axial capacities of drilled shafts using results of Cone Penetration Tests (CPT). The three methods to estimate failure loads are: (1) Nottingham method, (2) Laboratoire des Ponts et Chaussees method (LPC), and (3) the Poulos and Davis method. Comparisons are made to assess the accuracy and dependability of each predictive method. Analyses of results indicate that the LPC method provides the most reliable predictions for axial capacities of drilled shafts in clay

    Nitrogen and Plant Population in Corn Production

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    Phosphates in Crop Rotations in Lawrence County

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    The Reionization History in the Lognormal Model

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    We study the evolution of baryonic gas before the reionization in the lognormal (LN) model of cosmic clustering. We show that the thermal history of the universe around the reionization can roughly be divided into three epochs: 1) cold dark age z>zrz>z_r, in which baryon gas is neutral, and opaque to Lyα\alpha photons; 2) hot dark age zr>z>zgpz_r > z> z_{gp}, in which a predominant part of baryon gas is ionized and hot, but it is still opaque to Lyα\alpha photons; 3) bright age z<zgpz<z_{gp}, in which the universe is ionized highly enough to be transparent to Lyα\alpha photons. In the flat cold dark matter cosmological models given by WMAP and COBE, the difference of the two redshifts zrzgpz_r - z_{gp} is found to be as large as 10\sim 10 with zr17z_r\sim 17 and zgp7z_{gp}\sim 7. This reionization history naturally yields a high optical depth to the CMB τe0.120.19\tau_e \simeq 0.12 - 0.19 observed by the TE polarization of the WMAP, and a low redshift zgpz_{gp} of the appearance of the Lyα\alpha Gunn-Peterson trough zgp68z_{gp} \simeq 6 - 8 in QSO's absorption spectra. The reason why the universe stays long in an ionized, yet Lyα\alpha opaque, stage is because the first photo-ionization heats the intergalactic gas effectively and has balanced the gravitational clustering a long period of time. Therefore, the result of a high τe\tau_e and low zgpz_{gp} is a common feature of all the models considered. Besides the cosmological parameters, the only free parameter we used in the calculation is NionN_{ion}, the mean ionization photons produced by each baryon in collapsed objects. We take it to be 40 - 80 in the calculation.Comment: AAS Latex file, 29 pages, 6 figures included, accepted for publication in Ap

    Soft Color Enhancement of the Production of J/psi's by Neutrinos

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    We calculate the production of J/psi mesons by neutrino-nucleon collisions in fixed target experiments. Soft color, often referred to as color evaporation effects, enhance production cross sections due to the contribution of color octet states. Though still small, J/\psi production may be observable in present and future experiments like NuTeV and muon colliders.Comment: 7 pages, Revtex, 4 postscript figures, uses epsfig.st

    Negative-Parity States and beta-decays in odd Ho and Dy Nuclei with A=151,153

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    We have investigated the negative-parity states and electromagnetic transitions in 151,153^{151,153}Ho and 151,153^{151,153}Dy within the framework of the interacting boson fermion model 2 (IBFM-2). Spin assignments for some states with uncertain spin are made based on this calculation. Calculated excitation energies, electromagnetic transitions and branching ratios are compared with available experimental data and a good agreement is obtained. The model wave functions have been used to study β\beta-decays from Ho to Dy isotones, and the calculated logft\log ft values are close to the experimental data.Comment: 23 pages and 8 figures. accepted by Physical Review

    On Forward J/\psi Production at Fermilab Tevatron

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    The D0 Collaboration has recently reported the measurement of J/\psi production at low angle. We show here that the inclusion of color octet contributions in any framework is able to reproduce this data.Comment: 1 page, Revtex, uses epsfig.sty, 2 postscript figure
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